1. Field of the Invention
This invention relates to a technology of implementing control of light distribution corresponding to the travel condition and travel environment of a vehicle.
2. Description of the Related Art
At the time of controlling light emission from vehicle lamps such as automotive lamps, switching between high and low beams is well known. The high beam is used for irradiating a remote forward field, whereas the low beam is used at the time of passing cars coming from the opposite direction. It is also well known to switch filaments within one light source or switch high- and low-beam lamps that are prepared beforehand.
In such a conventional vehicular headlamp apparatus, however, high-beam light distribution and low-beam light distribution are independently employed, each of which is exclusively selected. Consequently, it is likely to make difficult the provision of light distribution offering a satisfactory visual field angle, depending on the travel condition and travel environment of a vehicle.